Biomedical subjects

M Landthaler

Publications and source records attributed to M Landthaler.

346 records · Page 20Linked to original sources

PubMedDate not supplied

Photosensitization of skin-derived cell lines by Dimegin [2,4-di-(alpha-methoxyethyl)-deuteroporphyrin IX] in vitro.

The deuteroporphyrin-IX derivative Dimegin [2,4-di-(alpha-methoxyethyl)-deuteroporphyrin IX] was investigated with respect to cellular uptake, intracellular localization and cell survival following photodynamic treatment in human cell lines derived from the skin (SCL1 and SCL2, squamous cell carcinoma; HaCaT keratinocytes; N1 fibroblasts). Using flow cytometry, we determined the cellular fluorescence as a marker of the uptake of Dimegin after incubation for 24 h. The intracellular localization of Dimegin was analysed using fluorescence microscopy and co-staining with fluorescent dyes specific for cell organelles. Following irradiation with an incoherent light source (580-740 nm) using a light dose of 24 J/cm2, phototoxicity was determined by means of trypan blue dye exclusion, MTT assays and growth curves. The relative Dimegin fluorescence of the different cell lines declined as follows: SCL1 > HaCaT > N1 > SCL2. Intracellular localization of Dimegin was found in the mitochondria. For all cell lines Dimegin concentrations above 15 microM yielded a significant phototoxic effect. The EC50 for SCL1 cells was 8.9 +/- 2.0 microM Dimegin. The EC50 for the cell lines increased as follows: SCL1 < HaCaT < N1 < SCL2, thus correlating with the cellular fluorescence of Dimegin. The results of the MTT assay were confirmed by trypan blue dye exclusion assay and growth curves. In conclusion, the study shows that Dimegin is an effective photosensitizer with a rapid mechanism of action in vitro, resulting in an immediate loss of plasma membrane integrity following irradiation.

Carcinoma, Squamous Cell↗

PubMedDate not supplied

Effects of mometasone furoate on human keratinocytes and fibroblasts in vitro.

The long-term treatment of inflammatory skin diseases with topical glucocorticoids is limited by their side effects such as skin atrophy, delayed wound healing and striae distensae. Mometasone furoate (MF) is a newly synthesized glucocorticoid with the advantage of increasing efficacy and reducing the number of adverse effects. The aim of our study was to compare the effects of MF and conventional fluorinated corticosteroids on a human keratinocyte cell line (HaCat) and human skin fibroblasts in vitro. Monolayer cultures of these cell lines were exposed to different concentrations of the active compounds for 5 days to analyze the influence on morphology and proliferation. Chemotaxis of HaCat cells and fibroblasts was studied in blind-well Boyden chambers using collagen type I and fibroblast-conditioned medium as a chemoattractant. Additionally, fibroblasts were used to investigate the contraction of collagen gels since lattice contraction appears to model the contraction of skin wounds. All glucocorticoids tested influenced fibroblast and keratinocyte proliferation in a dose-dependent manner, yet the effect was clearly more marked with fluorinated corticosteroids than with MF. Similar effects were obtained using the chemotaxis assay. At low concentrations (10(-9) M) MF exerted almost no influence, while the conventional fluorinated substances inhibited direct migration significantly. Contraction of collagen gels was inhibited completely by betamethasone valerate at high concentrations (10(-5)-10(-3) M), but only partially inhibited by MF at its highest concentration (10(-3) M). Although MF reveals high anti-inflammatory activity similar to that known for conventional fluorinated derivatives of corticosteroids, the study shows that MF has less effect in the tested in vitro systems. Therefore, it remains to be seen whether these data might indicate the possibility of a dissociation between the inflammatory activity and the inhibition of the biosynthetic capacities of fibroblasts and keratinocytes by modification of the steroidal structure of corticosteroids.

Administration, Topical↗

PubMedDate not supplied

Laser treatment of congenital vascular malformations.

Treatment of vascular malformations is one of the main indications for laser application in dermatology. The argon laser is suitable for coagulation of superficial lesions, the Nd:YAG laser for thicker ones. Vaporization or excision of vascular lesions can be performed by means of the CO2 laser. International standard of argon laser therapy of port wine stains are 60 to 70% good results in adult patients afflicted with red and purple lesions. In contrast argon laser therapy of pink lesions and of children is less successful. But more recently the flashlamp pumped dye laser has improved treatment results in children, since this laser acts much more vessel specific than the argon laser. Other congenital vascular lesions that respond to laser therapy are capillary hemangiomas, cavernous hemangiomas, and lymphangiomas. Future development may expand application of laser in the treatment of vascular malformations.

Adult↗

PubMedDate not supplied

[Verruciform xanthoma. Presentation of a case and review of the literature].

We describe a patient with a lesion on the nose, which clinically seemed a filiform wart; when the histological examination was performed we diagnosed a verruciform xanthoma. Looking at the literature we saw that the clinical diagnosis of this lesion had never been possible. Moreover, the histopathology always showed a peculiar pattern: a very dense infiltrate of foamy cells which completely removed the upper dermis and stopped at the basis of the rete ridges. Hyperlipemia was found in no cases, when specific tests were performed. Most cases reported were in the oral cavity. Age, sex and race do not seem to be relevant. The etiology of this lesion is unknown. Authors always discuss the pathogenesis, i.e. whether the first damage responsible for the formation of the foamy cells is in the epidermis or in the dermis. Other hypothesis have been suggested. Nevertheless, the majority of the Authors agree about the histiocytic origin of the xanthoma cells.

Diagnosis, Differential↗